从矿物学角度探讨芝罘岛黄土状黄土成因及古气候变化  

Origin of loess-like loess in Zhifu Island on mineralogic view and paleoclimatic change

作　　者：牛洪燕[1] 金秉福[1] 刘春暖[1] 宫立新[1] 

机构地区：[1]鲁东大学地理与规划学院,山东烟台264025

出　　处：《世界地质》2009年第4期476-484,共9页World Geology

基　　金：山东自然科学基金(重点)项目(Z2008E03)资助

摘　　要：沉积矿物是记录物源信息和古气候变迁的良好载体。通过显微镜碎屑矿物鉴定和黏土矿物X射线衍射峰能谱分析对芝罘岛黄土状黄土2个剖面13个样品进行处理,并对数据进行数学统计分析。结果表明,芝罘岛黄土状黄土矿物种类、矿物形态特征、磁铁矿和岩屑的高含量等都揭示了黄土来源的多源性和近源性,末次冰期时的海底平原沉积物以及洪积、残积物是芝罘岛黄土状黄土的重要物源,而西北内陆沙漠吹来的细颗粒物质相对较少。普通角闪石、绿帘石含量较高的黄土堆积后期是以远源沉积为主,且以风力搬运为主;磁铁矿、岩屑含量较高的早、中期是以近源沉积为主,搬运动力较复杂。根据黄土状黄土的剖面层序特征,碎屑矿物以及黏土矿物垂相变化特征,说明黄土堆积的早期,气候是相对温暖湿润的,之后变得寒冷干燥,后来又逐渐回暖,然后再转冷,呈现出末次冰期该地冷暖交替的气候旋回。Sedimentary are minerals good carrier to record material source and paleoclimatic change. Using microscope identification of detrital minerals and X-ray diffraction （ XRD）, the authors analyse the clay minerals of 13 samples from 2 profiles of loess-like loess in Zhifu Island, and the data by mathematical statistics. The results show the mineral taxa, morphological characteristics and the high contents of magnetite and deris revealed the multi-sources and near-derived features of the loess-like loess in Zhifu Island, and the main sources of loess are seabed plain, diluvium and residual sediments in the last glacial period, while thin sediments from Northwest inland desert are rare. The late period of loess accumulation with high contents of hornblende and epidote is mainly farsource sedimentary with wind transport, and the early and middle periods of loess accumulation with high contents of magnetite and deris are mainly near-source sedimentary with complex transport. Profile sequence characteristics of loess and vertical variational characteristics of detrital and clay minerals indicate the climate in Zhifu Island was warm and wet in early period of loess accumulation, then changed to cold and dry, after that turned to warm, and to cold again. The fact shows the climate cycle of cold-warm alternate in the last glacial period.

关 键 词：芝罘岛 黄土状黄土 碎屑矿物 黏土矿物 物质来源 古气候变化 

分 类 号：P532[天文地球—古生物学与地层学] P588.23[天文地球—地质学]